Floristic treatment of species of the genus Peltigera, the first made in light of recent taxonomic developments. The report summarizes the diversity of the genus occurring in Alberta and makes available a comprehensive key to the local species. A morphological description is provided for all species and each is illustrated by photographs. All Albertan specimens examined were mapped. A discussion on variation and some information on ecology and distribution in Alberta follows each description. General distribution patterns for North America are based on literature and additional North American collections examined.